It is known to provide in-mold labelling systems for blow molds of the split half type wherein the blow molds rotate in a circular pattern and open radially. Such blow mold labelling systems are fixed on the carriage of the machine frame and when the blow molds are opened and immediately after the discharge of a blow molded article therefrom, label applicators are moved transversely into the path of the rotating blow molds for placing labels into one or both of the mold halves.